On 4/20/07, Timothy Redaelli <drizzt@g.o> wrote:
> Can you try to recompile the kernel with gcc 4 but with -O0?
> cd /usr/src/sys/i386/compile/GENERIC ; COPTFLAGS=-O0 make

I can confirm that compiling with gcc-4 and COPTFLAGS=-O0 produces a
working kernel (i.e. no malformed tcp packets).  This was after I
found that the gcc41 patch is also not causing the problem.  After
getting a working kernel with gcc-4 I went back and used the default
COPTFLAGS again and it broke again.  So I think this gives us a fair
amount of certainty that the problem is caused by gcc-4 optimizations.

As to the reason why some FreeBSD users experience this and other do
not, I am not sure.  The symptoms (broken TCP traffic to some sites)
depend entirely upon the sites you are connecting to and how your
connections are routed.  So it is possible that somebody could have
this problem by not realize it.

However, using tcpdump I can tell that some machines apparently do not
experience this problem, so it may be processor-specific (which makes
sense given that it is an optimization problem).  I use a Pentium M.
What are other people using that have been affected by the problem?

-- 
Nathan Smith
ndansmith@...
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